A pesticide suspension is a homogeneous mixture of small solid particles of pesticide suspended in a liquid medium. The growth of microorganisms in the pesticide suspension can cause a solid precipitate to form and therefore, a loss of homogeneity in the mixture. Formation of the precipitate and the loss of homogeneity can result in product failure due to non-uniform applications of the pesticide, and plugging of strainers and nozzles used with application equipment.
A practice developed in the art of combining or formulating the pesticide compounds with a preservative to reduce or eliminate the growth of microorganisms in pesticide suspensions. U.S. Pat. No. 5,283,231 describes formaldehyde, sodium benzoate, glutaraldehyde, and pentachlorophenol, as effective preservatives to prevent microbial spoiling in low-melting dinitroaniline pesticide suspensions.
Not all preservatives are effective against all types of microorganisms, in all pesticide suspensions. Thus, there is a need in the art to determine specific preservatives that are effective in a particular flowable aqueous pesticide composition (i) to reduce or eliminate the growth of microorganisms, (ii) while being easy to handle during preparation and use, and (iii) maintaining an excellent shelf-life even during extended storage.